The use of elastomeric materials to improve fit is well known in many different arts. Prior art articles, such as garments, both durable and disposable, have incorporated bands of stretched elastomeric material in waistbands, legbands, anklebands, cuffbands, headbands and the like.
One common class of elastomeric materials used in these applications is comprised of "live" elastics, such as natural rubber. These are typically secured to the article to be elasticized while they are held in a tensioned condition, or the article must be foreshortened while the end points of the elastomeric member are secured thereto. The former operation, i.e., applying the elastics in a tensioned condition, is often difficult to do, particularly at high speed. It is even more difficult when the desired direction of elasticity is substantially perpendicular to the direction of article or web travel. While the latter approach, i.e., foreshortening the article and securing the end points of the untensioned elastics thereto, does permit the elastomeric material to be applied in a substantially untensioned condition, it is generally ineffective to produce uniform shirring or gathering of the article due to the fact that only the end points of the elastic member are secured thereto.
Another prior art approach which has been developed over the years relates to the use of heat shrinkable elastomeric materials. Such materials can be applied in a substantially untensioned state and thereafter caused to shrink in a predetermined direction by the application of an external stimulus, such as heat. While this approach has been utilized with reasonable success in producing articles such as disposable diapers having elasticized waistbands, heat shrinkable elastomeric materials are generally more expensive than "live" elastomeric materials. In addition, the amount of elastic recovery obtainable with such materials is generally less than for prestretched "live" elastomeric materials. Finally, the post application stimulus is often difficult to apply in a reliable fashion, and the need to apply the post application stimulus may impose restraints on the types of materials which can be employed adjacent the heat shrinkable elastomeric material and/or the methods of assembly used to construct the article.
More recently, an elastically shirrable segment comprising a "live" elastomeric member which is maintained in a prestretched and tensioned condition in the desired direction of article shirring by a rigidifying member has been developed. This elastically shirrable segment overcomes many of the difficulties associated with the aforementioned prior art elasticization processes. Details of the elastically shirrable segment are fully described in commonly assigned European Patent Application No. 0,242,175 filed in the names of James Clark Baird, Delmar Ray Muckenfuhs, Thurman J. Koger II, and Milton Daniel Spahni, and entitled "Article Including Segment Which Is Elastically Shirrable After Manufacture", said application being published on Oct. 21, 1987, and hereby incorporated herein by reference.
The aforementioned commonly assigned European Patent Application of Baird et al. discloses how the aforementioned elastically shirrable segments can be attached to an article to provide shirring in whatever direction is desired upon effecting separation of or relative movement between the rigidifying member and the prestretched and tensioned elastomeric member.
It is an object of the present invention to provide an elasticized fastening system incorporating an elastically shirrable segment of the type generally disclosed in the aforementioned commonly assigned European Patent Application of Baird et al.
It is a further object of the present invention to provide such a fastening system wherein tension is automatically released in the prestretched and tensioned elastomeric member when the end user applies the article in question to an object of substantially predetermined cross-section.
It is another object of the present invention to provide such a fastening system, wherein the rigidifying member includes a releasable portion which not only maintains the prestretched elastomeric member in tension until the article is applied by the end user, but which also may be used to secure the first and second end portions of the article to one another.
It is still another object of the present invention to provide high speed method and apparatus for continuously assembling and applying such elasticized fastening systems which are capable of shirring the article to which they are affixed in a direction substantially perpendicular to the direction in which the web travels during the article manufacturing process whenever tension in the prestretched and tensioned elastomeric member is released.